P- Picture viewing at diagnostic, reporting, consulting and remote workstations
A- Archiving images using short or long-term storage devices
C- Communications using local or wide area networks or public communication services.
S- Systems that include modality interfaces and gateways the veterinary hospital and departmental information systems, offering one integrated system to the user

Basically a PACS system is used to store and retrieve images. Once an image is generated, the image is sent to a local PACS server (some are web based) which stores the image in a local archive. Redundancy (backup) is always warranted so a second image is also stored in an off site archive. When a user wants to retrieve the image, a message is sent to the local PACS server which retrieves it from the archive.

If you are considering purchasing a digital radiography system think about this...What do you plan on doing with your digital radiographs once you acquire them? Will you burn them onto CD's? Store them in individual folders on a hard drive? Print them on an inkjet printer? These are all options that veterinarians have employed. However, each of these methods is inherently inefficient and image retrieval can be a nuisance.

A PACS system is the only solution that allows you to efficiently store and retrieve your images. Furthermore, it is the only solution that will interface with your hospital information system to allow you to move toward the ultimate goal of digital radiography which is the paperless practice. A PACS system will provide you with the ability to have all of your patients previous radiographs immediately available every time you look at their record. A PACS system prevents lost radiographs and the need to search for old films.

A firm understanding of what a PACS system does and why it is important is necessary before you ever talk to a vendor about purchasing a digital radiography system. You will find that most vendors do an excellent job of selling their digital radiography equipment (CR/DR) but they sell their PACS solutions as an afterthought. Many vendors do not even mention the need for a PACS system in their initial sales pitch. For example, last week, I met with a vendor that said.."For $44,000.00 I can have a CR system installed in your practice!" Unfortunately, he forgot to mention that this price did not include a PACS system and that a PACS system was necessary to run the system. Furthermore, he didn't know "exactly how much" a PACS system would cost. He said that he would get back to me with that price...I am still waiting.

It cannot be overstated that the decision about which PACS system one chooses to use may be the most important decision you make regarding how you manage your digital images. If the images cannot be retrieved, the system is inefficient, the system cannot be easily (and inexpensively) upgraded in the future, or the system cannot integrate with the radiology information system (RIS) and the hospital information system (HIS) and all of the imaging modalities in the hospital many of the benefits of a filmless environment are lost. It is my recommendation that, if possible, the PACS system be purchased through the same vendor that sells your digital radiography equipment. This will prevent one vendor blaming the other vendor when the two systems do not communicate. Furthermore, because the PACS system may be nearly as expensive as the digital radiography system, purchasing these two systems as a bundle may ultimately decrease the cost of your digital radiography installation.

It should be noted that a PACS system should be able to archive and distribute all of the digital images generated at a your hospital. All of the imaging modalities such as ultrasound, CT, MRI, and digital photography should (theoretically) be associated with the PACS systems so the cost savings associated with filmless digital radiography can be extended to these other imaging modalities as well. The following is an image of a PACS system to show, diagrammatically, how a PACS system can integrate a hospitals imaging system.